Proposal Summary/Abstract American Indians and Alaska Natives (AIAN) are disproportionately impacted by adverse outcomes associated with risky sexual behavior and substance use. Literature suggests these health harming behaviors begin in early adolescence, before the age of 13. Therefore, early intervention that focuses on precursors to risky behaviors is essential to preventing early sexual experience, substance use, and the associated negative health outcomes. Unfortunately, there is limited research that focuses on the development of risk resistive skills, such as self-efficacy, on reducing risky health behaviors among AIAN early adolescents. This study proposes to address this gap by examining the development of self-efficacy and the factors that shape the identified trajectories in order to effectively intervene. Because AIAN youth experience higher rates of exposure to adverse social and physical environment, which is hypothesized to alter the development of risk resistive skills, this study looks at the interplay between adversity and the development of substance use and sexual risk restive skills. The proposed study is a secondary data analysis that provides the opportunity to develop advanced training in latent variable methodologies and their application to an underserved AIAN adolescent community. Specific statistical skills in the training plan include 1) mediated structural equation modeling to assess the cross- sectional relationships among adversity, substance use, and sex resistive self-efficacy; 2) latent growth curve modeling and growth mixture modeling to analyze complex longitudinal relationships among variables; and 3) assessment of the function of time varying covariates when analyzing youth development trajectories. In addition to developing research design and statistical analyses techniques, the proposed study will allow for the development of professional skills in manuscript and proposal planning, writing, submission, and revision; and development of a professional research network to generate collaboration and innovation in the field. Further, findings from this research have the potential to inform policies and interventions that address AIAN health disparities by targeting precursors of early adolescence to prevent multiple risk behaviors in later years.